There is a robot that has been continuously operating since 1996. - Apparently.
In 1996, the robot called "Sojourner" was launched to Mars by NASA's Mars Pathfinder mission. Weighing in at just 23 pounds, Sojourner was the first robot to explore the Martian surface. It operated for 83 days, covering a total distance of 3 miles and sending back vital data about the Martian geology. Despite being over 25 years old, Sojourner's legacy as the longest-operating robot on Mars remains to this day.